An overview of the most recent status of Solid Oxide Cell (SOC) and stack developments within TNO will be presented. The techno-economic analysis of methanol synthesis using co-electrolysis of CO2 and H2O as the source of the required syngas for methanol synthesis demonstrates the feasibility of the methanol synthesis at a production cost of < 700 €/ton. The in-house solid oxide cell manufacturing development has resulted in high porosity fuel electrode-supported-cells with cell dimensions up to 20x20 cm2, capable of high performance steam-, co- and CO2 electrolysis. Both an experimental proof of co-electrolysis of CO2 and steam towards a syngas composition suited for methanol synthesis and CO2-electrolysis have been realized on a single cell level, making use of 10x10 cm2 electrode-supported cells. CO2-electrolysis towards CO, demonstrated CO2-conversion levels up to 60%.

Since 2018, TNO has started the development of a next generation Solid Oxide Cell (SOC) electrolyzer technology to provide high performance and low-cost technological options for the electrification of the chemicals and fuels industry. The main emphasis of TNO developments on the SOC technology focuses on 1/ high temperature CO2-electrolysis and co-electrolysis of steam and CO2 for industrial CO2 re-use processes, aiming for green fuels and chemicals generation, and 2/ large scale high temperature steam electrolysis for hydrogen generation in existing industrial infrastructure, like refineries or ammonia plants. The ambition of the SOC technology development program is to assist the whole value chain, from cell manufacturing to end-users, by making the technology economically viable. This can be achieved through cost reduction at both system (< 500 €/kW in 2030) and stack level (< 200 €/kW in 2030), and improved stack lifetime (up to 60,000 hours by 2030). To achieve these performance and economical objectives, TNO focuses its SOC technology R&D activities on 1/ cell and stack development and 2/ techno-economic and business case studies on SOC technology integration in the industrial environment. These activities aim to support SOC technology demonstrations in the industrial environment. In the last two years, new SOC manufacturing and testing infrastructures have been created within TNO to this end. The Faraday Lab, an open innovation lab to develop the SOC technology on cell and stack level, has been realised. A lab-scale manufacturing line located in Petten, the Netherlands, focuses on developing high performance planar electrode- and electrolyte-supported solid oxide cells with cell dimensions up to 30x30 cm2, based on low-cost tape casting and screen-printing manufacturing techniques. Electrochemical testing facilities, including test stations for single cell testing from button cell to potentially 30x30 cm2 cell area and short stack testing up to 1 kW, have been realised at TNO locations in Petten and Delft, the Netherlands. The new test stations have been developed to assess cells and stacks performance and lifetime under steam-, CO2-electrolysis, steam/CO2 co-electrolysis and reversible SOFC/SOE operations. The SOC manufacturing and testing facilities are available for collaborations with industrial and academic partners directly and/or in national and European funding scheme-based collaborations. In addition, since 2020 TNO started the design of the “Field Lab Industrial Electrification”, a testing platform offering the possibility of testing multi-kW to MW size Solid Oxide Electrolyser pilots at the key location of Rotterdam Harbour, where industrial companies can benefit from the process integration possibilities of the SOC technology in an industrial environment. During the conference, an overview of the most recent status of SOC cell and stack developments within TNO will be presented with main emphasis on steam/CO2 co-electrolysis and CO2-electrolysis applications. The status of the cell and stack development, including the R&D efforts on carbon resistant fuel electrode development, cell performance and lifetime improvements and the scale-up of the SOC dimensions up to 30x30 cm2 will be discussed. As highlight for this communication, the first performance results of a fuel electrode-supported cells (10x10 cm2 with an active electrode area of 81 cm2) under steam/CO2 co-electrolysis conditions, aiming towards a syngas composition for methanol synthesis (m= (H2-CO2)/(CO+CO2) =2), are shown in the graph below. Figure 1

This paper illustrates the operational difficulties arising from simultaneously performing exothermic and endothermic reactions, and demonstrates that a plant can be built and safely operated by integrating the design and plantwide control issues. The behaviour of reactorseparation -recycle systems carrying the coupled reactions A →P + Q (endo) and B + Q → R (exo) is investigated. Irrespective of the control structure, state multiplicity cannot be removed if the intermediate component Q is recycled. Therefore, the chemical reactor should be designed such that the recycle of Q can be avoided without economic penalty. The theoretical findings are applied to the design and control of a plant coupling ethylbenzene dehydrogenation and nitrobenzene hydrogenation for simultaneous production of styrene and aniline. After plant design, a rigorous dynamic model is developed using AspenDynamics. A plantwide control structure is implemented and shown to be able to achieve stable operation. Production rate changes of reasonable magnitude can be achieved by changing the reactor-inlet flow rates or bed-inlet temperature.

A cubic equation of state, GEOS, with quadratic mixing rules and two adjustable parameters was used to calculate the solid � gas equilibrium in aromatic compounds + supercritical carbon dioxide systems. The results are in good agreement with the experimental data for temperatures between 308 K and 343 K and pressures up to 360 bar. The adjustable parameters kij and lij used in the mixing rules vary linearly with the temperature or remain constant for the investigated systems. Based on this observation, the binary interaction parameters and hence, the solubilities of the studied solid aromatic compounds in supercritical carbon dioxide can be predicted.